Transport Parameters of a-Si

In crystalline semiconductors, the investigation of electronic transport properties (measured as a function of temperature or electric or magnetic field strength) can provide information on the scattering mechanism, carrier concentration and mobility, Fermi-level position, etc. Yet none of these latter quantities is obtained directly from the experiment Theoretical models for the transport are fitted to the experiment data to obtain transport parameters. The validity of both transport theories and transport parameters is checked by the quality of the fit and by a comparison of parameters obtained from different transport experiments. 

The conductivity a relates the current density j to the external electric field E as 

For unipolar conduction and for a single conduction mechanism, i.e., for identical charge carriers, 

The Seebeck coefficient S is defined by the electric field generated in the 

The Peltier energy — ell has a simple interpretation as the mean energy with respect to the Fermi energy transported per charge carrier. 

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